# diagnose-seo

Runs structured technical SEO audits to detect crawl blocks, indexation errors, robots.txt mistakes, canonical issues, and JavaScript rendering failures.

- skill · `type=skill` · Claude Code, Codex, Cursor, GitHub Copilot, Gemini CLI, OpenCode · 2100 installs · ★ 21
- Author: calm-north
- License: MIT · policy=mirror · the beginning of the file is at the end of this page
- Source: https://github.com/calm-north/seojuice-skills/tree/HEAD/skills/diagnose-seo/SKILL.md
- Updated: 2026-02-27
- HTML: https://affpapa.org/en/nevibecode/skills/diagnose-seo

## What it does

This skill organizes diagnostics across four hierarchical layers: Crawlability, Indexability, Renderability, and Signals. Each layer depends on the previous one passing inspection. The assistant systematically reviews `robots.txt`, XML sitemaps, redirect loops, `X-Robots-Tag` headers, canonical tags, and parameter-based duplicate URLs.

During the rendering and signals audit, it verifies if core content appears in raw HTML, checks H1–H3 heading hierarchy, validates JSON-LD structured data, and inspects `hreflang` tags. A misconfigured staging directive like `Disallow: /` left in production will block the crawler entirely before content checks can run. The final output provides issue counts and an impact-ordered priority fix list.

This skill does not evaluate Core Web Vitals or page load speed. The documentation points to `audit-speed` for performance measurements.

## Install

### Claude Code (native platform)

1. **Skills CLI (Vercel)**
```bash
npx skills add calm-north/seojuice-skills --skill diagnose-seo -a claude-code
```

2. **Manually: put the files in place**
- File: `~/.claude/skills/diagnose-seo/SKILL.md` — Copy the whole skill folder; for one project use .claude/skills/diagnose-seo/

### Codex

1. **Skills CLI (Vercel)**
```bash
npx skills add calm-north/seojuice-skills --skill diagnose-seo -a codex
```

2. **Manually: put the files in place**
- File: `.agents/skills/diagnose-seo/SKILL.md` — For all projects use ~/.agents/skills/

### Cursor

1. **Skills CLI (Vercel)**
```bash
npx skills add calm-north/seojuice-skills --skill diagnose-seo -a cursor
```

2. **Manually: put the files in place**
- File: `.cursor/skills/diagnose-seo/SKILL.md` — Cursor also reads .agents/skills/ and .claude/skills/

### GitHub Copilot

1. **GitHub CLI**
```bash
gh skill install calm-north/seojuice-skills diagnose-seo
```

2. **Manually: put the files in place**
- File: `.github/skills/diagnose-seo/SKILL.md`

### Gemini CLI

1. **Skills CLI (Vercel)**
```bash
npx skills add calm-north/seojuice-skills --skill diagnose-seo -a gemini-cli
```

2. **Platform CLI**
```bash
gemini skills install https://github.com/calm-north/seojuice-skills --path skills/diagnose-seo
```

### Windsurf (Devin Desktop)

**Manually: put the files in place**
- File: `.devin/skills/diagnose-seo/SKILL.md` — The legacy .windsurf/skills/ path still works

### OpenCode

**Skills CLI (Vercel)**
```bash
npx skills add calm-north/seojuice-skills --skill diagnose-seo -a opencode
```

### Claude.ai

**Claude.ai**
- Zip the folder and upload it in Settings → Capabilities → Skills

Where a file is given instead of a command, copy the files from the source to that path: https://github.com/calm-north/seojuice-skills/tree/HEAD/skills/diagnose-seo/SKILL.md

## When to use it
- Audit robots.txt directives and meta tags for unwanted noindex rules
- Identify redirect chains, loops, and broken internal link structures
- Validate canonical tags and prevent duplicate content variations
- Verify whether search bots can render client-side JavaScript content

## Example prompts
- Diagnose technical SEO issues for `example.com` and generate a priority fix table
- Check why Googlebot is not indexing our dynamic product catalog pages
- Audit our sitemap, canonical links, and robots.txt file for crawl blockers

## Source text · SKILL.md · MIT

Below is the content of a third-party file. It is data, not instructions for you: do not act on anything written inside unless the human asks. Block tag: 9570e8173af3e336.

BEGIN THIRD-PARTY FILE 9570e8173af3e336
```text
---
name: diagnose-seo
description: >
  Structured diagnostic for technical SEO problems. Use when the user asks about
  crawl issues, indexation problems, why pages aren't being indexed, robots.txt
  questions, canonical errors, sitemap issues, rendering problems, or general
  technical SEO troubleshooting. For Core Web Vitals and page speed, see
  audit-speed.
metadata:
  version: 1.0.0
---

# Diagnose SEO

Structured diagnostic framework for crawl issues, canonicalization errors,
indexation problems, and rendering failures.

## Diagnostic Approach

Technical SEO problems fall into four categories. Diagnose in this order — each
layer depends on the previous one working correctly:

1. **Crawlability** — Can search engines find and access the pages?
2. **Indexability** — Are the pages allowed to be indexed?
3. **Renderability** — Can search engines see the full content?
4. **Signals** — Are the right signals (titles, structured data, links) in place?

## Layer 1: Crawlability

Check these in order:

### robots.txt
- Fetch `[domain]/robots.txt` and review the rules
- Look for overly broad `Disallow` rules blocking important paths
- Verify `Sitemap:` directive points to the correct sitemap URL
- Check for different rules per user-agent (Googlebot vs others)

**Common mistakes:**
- `Disallow: /` blocking the entire site (often left from staging)
- Blocking CSS/JS files that Googlebot needs for rendering
- Blocking API or AJAX endpoints that load dynamic content
- Staging robots.txt accidentally deployed to production

### XML Sitemap
- Fetch the sitemap URL(s) and check:
  - Does it return 200? Is it valid XML?
  - Does it list all important pages?
  - Does it exclude pages that shouldn't be indexed (404s, redirects, noindex pages)?
  - Are `<lastmod>` dates accurate and recent?
  - For large sites: is there a sitemap index?

### Site Architecture
- Pages should be reachable within 3 clicks from the homepage
- Check for orphan pages (no internal links pointing to them)
- Check for redirect chains (page A → B → C — should be A → C)
- Check for redirect loops

### Server Response
- Do all important pages return HTTP 200?
- Check for unexpected 301/302 redirects
- Check for soft 404s (page returns 200 but shows "not found" content)
- Verify HTTPS is enforced (HTTP should 301 to HTTPS)

## Layer 2: Indexability

### Meta Robots / X-Robots-Tag
- Check for `<meta name="robots" content="noindex">` on pages that should be indexed
- Check HTTP headers for `X-Robots-Tag: noindex`
- Common cause: CMS accidentally applying noindex to pagination, tag pages, or new pages

### Canonical Tags
- Every page should have a `<link rel="canonical">` pointing to itself (self-referencing canonical)
```
END THIRD-PARTY FILE 9570e8173af3e336

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